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US 8,897,465 B2Granted
Class D micro-speaker
AssigneeRobert Bosch GmbH
InventorJohn M. Muza
Life of this patent
Estimating the term…
Abstract
A micro-speaker. The micro-speaker includes a first plate, a second plate, and a diaphragm. The first plate is biased to a first voltage. The second plate is biased to a second voltage. The diaphragm is positioned between the first plate and the second plate and is configured to receive a digital signal. The digital signal causes the diaphragm to cycle between fully displaced toward the first plate and fully displaced toward the second plate, creating air pressure pulses that mimic the digital signal.
Claims18
A micro-speaker comprising:
- a first plate including a plurality of openings and biased to a first voltage;
- a second plate including a plurality of openings and biased to a second voltage;
- and
- a diaphragm positioned between the first plate and the second plate and configured to receive a digital signal, the digital signal causing the diaphragm to cycle between a first fully displaced position near the first plate and a second fully displaced position near the second plate, forcing air through the plurality of openings in the first plate and the second plate, and creating air pressure pulses that mimic the digital signal;
- and
- wherein the digital signal creates a sufficient bias such that the diaphragm is fully displaced immediately and does not stop at any point between the first fully displaced position and the second fully displaced position, the first fully displaced position being a first distance from the first plate such that the diaphragm does not contact the first plate, and the second fully displaced position being a second distance from the second plate such that the diaphragm does not contact the second plate.
3 more elements
A method of producing sound waves, the method comprising:
- receiving an analog electric signal representative of the sound waves to be produced;
- generating a high-frequency signal;
- producing a pulse-width-modulated signal based on the analog electric signal and the high-frequency signal;
- amplifying the pulse-width-modulated signal;
- applying the amplified pulse-width-modulated signal to a diaphragm of a speaker, the diaphragm positioned between a first plate and a second plate, the first plate having a first electrical bias and the second plate having a second electrical bias, the amplified pulse-width-modulated signal causing the diaphragm to cycle between a fully displaced position toward the first plate and a second fully displaced position toward the second plate, creating air pressure pulses that are forced through openings in the first and second plates and mimic the pulse-width-modulated signal;
- and
- wherein the pulse-width-modulated signal creates a sufficient bias such that the diaphragm is fully displaced immediately and does not stop at any point between the first fully displaced position and the second fully displaced position, the first fully displaced position being a first distance from the first plate such that the diaphragm does not contact the first plate, and the second fully displaced position being a second distance from the second plate such that the diaphragm does not contact the second plate.
4 more elements
Dependencies are inferred from the claim text.